On Tue, 2005-04-19 at 21:36 +0200, Eric Botcazou wrote: > > > For 3.3 and 3.4, this was "fixed" by not recording memory equivalences > > > that have the infamous RTX_UNCHANGING_P flag set. > > > > Also a possibility. Making the equivalent change (!MEM_READONLY_P) > > appears to do the trick for mainline. > > Yes, but that's of course not optimal, unnecessary spills are generated. True. That's one of the reasons why I mentioned the possibility of finding these insns and simply removing them.
Think about it for a while -- given a SET where the SET_SRC is a pseudo which did not get a hard register and is equivalenced to a read-only memory location, then the SET must be dead as it can only be setting the memory location to the value already in the memory location. jeff
